178 
FXUS66 KSGX 220538
AFDSGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
935 PM PST SAT NOV 21 2009

.SYNOPSIS...MOSTLY CLEAR WITH A WARMING TREND THROUGH THE MIDDLE OF 
NEXT WEEK UNDER BUILDING HIGH PRESSURE AND WEAK OFFSHORE FLOW.

&&

.DISCUSSION...FOR SOUTHWEST CALIFORNIA INCLUDING SAN DIEGO... 
ORANGE...SOUTHWEST SAN BERNARDINO AND WEST RIVERSIDE COUNTIES.

TEMPERATURES TODAY WERE SEVERAL DEGREES LOWER THAN YESTERDAY...AND 
IN SOME PLACES (BEAUMONT) IT WAS A FULL 10 DEGREES LOWER. THE 
DOWNWARD SLIDE CONTINUES TONIGHT WHERE IT WILL BE QUITE COOL WITH 
TEMPS BOTTOMING OUT IN THE UPPER 30S AND LOW 40S IN THE INLAND 
VALLEYS. LOWS WILL FALL INTO THE TEENS IN THE SOME OF THE COLD AIR 
DRAINAGE AREAS OF THE SAN BERNARDINO MOUNTAINS (BALDWIN LAKE).

CLOUD COVER FROM THE MARINE LAYER THIS EVENING IS SPOTTY. MOST OF 
THE REGION WAS CLEAR AT 9 PM. WEAK RIDGING ALOFT AND LIGHT OFFSHORE 
FLOW WILL KEEP SKIES MOSTLY CLEAR THROUGH SUNDAY MORNING. 
TEMPERATURES WILL REBOUND QUICKLY TOMORROW AFTER SUNRISE. 

ON SUNDAY NIGHT AND MONDAY WEAK UPPER LEVEL TROUGHING WILL BRIEFLY 
NEUTRALIZE THE OFFSHORE PRESSURE PATTERN. BUT IT TURNS AROUND 
QUICKLY ON MONDAY NIGHT AND TUESDAY WHEN A SLIGHTLY STRONGER 
OFFSHORE FLOW ARRIVES. EXPECT CLEAR SKIES AND WARMER WEATHER EACH 
DAY THROUGH THURSDAY UNDER THIS WEATHER PATTERN. WEAK TO MODERATE 
SANTA ANA WINDS ARE FORECAST TUESDAY THROUGH THURSDAY...BUT WILL 
REMAIN BELOW ADVISORY LEVELS.

COOLING NEXT WEEKEND WHEN THE HIGH OVER THE GREAT BASIN IS REPLACED 
BY A PACIFIC TROUGH BRINGING COOLER WEATHER AND THE RETURN OF 
ONSHORE FLOW. 

&&

.AVIATION...
230530Z...THE MARINE LAYER LOW CLOUDS ARE EXPECTED TO DISSIPATE BY 
EARLY SUNDAY MORNING AS WEAK OFFSHORE FLOW CONTINUES TO DEVELOP OVER 
THE REGION. MOSTLY VFR CONDITIONS THROUGH MONDAY. LIGHT OFFSHORE 
FLOW NIGHTS AND MORNINGS...WITH SOUTHWEST TO WEST SEA BREEZE WINDS 
IN THE AFTERNOONS.

&&

.FIRE WEATHER...
NO SHORT TERM FIRE WEATHER CONCERNS. NEXT CONCERN IS THE PROLONGED 
OFFSHORE WIND PATTERN FOR NEXT WEEK. THIS STILL LOOKS LIKE A WEAK TO 
BRIEFLY MODERATE EVENT...PEAKING ON TUESDAY. ADDED FORECAST WIND 
GUSTS AND RH VALUES TO THE EXTENDED PORTION OF EACH FIRE WEATHER 
ZONE FORECAST IN THIS AFTERNOONS. LOOKING FURTHER OUT...ASSUMING THE 
MODELS ARE DEAD ON ACCURATE WITH THE STRENGTH AND POSITION OF THE 
RIDGE...A MUCH STRONGER OFFSHORE WIND EVENT IS ADVERTISED TO FINISH 
OUT THE MONTH OF NOVEMBER.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

PUBLIC...MOEDE
AVIATION...SMALL
FIRE WEATHER...BALFOUR